CARDIAC-HYPERTROPHY AND ARTERIAL COMPLIANCE AFTER ANTIHYPERTENSIVE THERAPY

Cardiac hypertrophy in hypertension is related to increased peripheral vascular resistance and reduced aortic compliance. Non-invasive measurement of pulse wave velocities and systolo-diastolic variations of the diameter of the aortic arch show that an increase in the elastic modulus of the aorta is closely related to the increase in cardiac mass. This relationship holds even after correction for mean arterial pressure. Therefore, it has been suggested that, in hypertension, the decreased aortic compliance leads to a disproportionate increase in systolic blood pressure and end systolic wall stress, predisposing to cardiac hypertrophy. The blood pressure, arterial haemodynamics of the forearm (by pulsed Doppler flow measurement) and echocardiographic parameters were studied in 16 patients with permanent essential hypertension, before and 3 months after treatment with perindopril, an ACE inhibitor. In a simple blinded study versus placebo, perindopril was shown to significantly reduce the blood pressure (p < 0.01) while brachial blood flow increased (p < 0.01) because of a simultaneous increase in blood flow velocity and arterial diameter. During 5 minutes' occlusion at the wrist, blood flow velocity decreased more in patients taking perindopril than those on placebo (p < 0.01) whilst the reduction in arterial diameter was equivalent, indicating that the increase in arterial diameter with perindopril could not be explained by flow-dependant dilatation alone but by a direct effect of the drug on the artery. During the treatment phase, brachial arterial compliance increased (p < 0.01) and pulse wave velocity decreased (p < 0.01) and there was no change in arterial shear stress defined as the product of mean blood pressure and arterial diameter. Four weeks after withdrawing treatment, the blood pressure and forearm blood flow haemodynamics had returned to their base line values. Cardiac mass was significantly reduced with perindopril (p < 0.01) and remained decreased four weeks after stopping the drug. After treatment with an ACE inhibitor, perindopril, there was a dissociation in time between the antihypertensive effects and the structural arterial and cardiac changes : this showed a significant beneficial effect of perindopril on cardiovascular remodeling, a phenomenon of adaptation to hypertension.